Perforating device for rubber sheets



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UNITED STATES PATENT OFFICE.

JOHN R. GAMMETER, 0F AKRON, OHIO, ASSIGNOR T0 THE B. GOODRICH COEPANY,

OF NEW YORK,- N. Y., A CORPORATION 0F NEW YORK.

' PERFORATING DEVICE FOR RUBBER SHEETS.

Application led December 3, 1924. Serial No. 753,638.

A backing plate 25 is detachably secured This invention relates. to machines for perforating sheets of rubber and similar elastic material, and'has for an object to provide for performing operations of this sheets of various shapes and sizes, to leave imperforatea margins of desired widths on the sheets irrespective ofthe size or shape of the sheet, and to form therein with the perforations designs of varied character. A further object'is to provide an apparatus which will accurately, quickly'. and economically perforate a thin elastic, soft-rubber sheet.

Of the accompanying drawings, Fig.' l is a plan view of a' preferred embodiment of my perforating device, parts being broken away to show the rubber sheet and punch plate; Fig. 2 is a section on an enlarged scale, on line 2-2 of Fig. 1; Fig. 3 is a reverse plan view of the device of Fig. 1. parts being broken away; Fig. 4 is an enlarged sectional view on line 4-4 of Fig. 3; and Fig. 5 is a detailed sectional view on line 5-,5 of Fig.v 2.

In the drawings, 10 is a die-plate of steel, or other suitable material, having aligne rows of apertures 11 regularly spaced and substantially coextensive with the plate, the vmarginal portions only being imperforate. The apertures 11 as shown, are in quadrangularly disposed rows, but it is obvious that the perforations may be placed in equilateral triangular relation' to each other, or in other relative. positions. Each of the apertures 11 has an enlarged portion 12 on the inner sideV of theplate 10 in which a hollow, cylindrical die member 13 of hardened steel is disposed. A

Hinged to die vplate 10 is apunch plate 15, coextensive in size with the die plate 10, and having apertures 16 axiallyl laligned with the die apertures 11. As shown, the plates 10 and 15 are connected by hinges 17 which have their leaves 18 inset into the inner Surfaces of the plates 10 and 15 and secured thereto by rivets 19. Accurate spacing of the plates 10 and 15, and alignment of the apertures 11 and 16, when the plates are in closed position, are attained by means of the square dowel strips 20 diagonally disposed and mounted along the marginal edges of the plate 10. which strips fit into notches 21 in spacer blocks 22 secured to the plates 15, as by bolts 23.

to the plate 15 in parallel spaced relation `thereto, the securing means being such as to permit relative limited movements therebetween .in a direction axially of the apertures 16 in the plate 15. As shown, the plate 25 has swaged therein at its four corners 11p-standing studs 26 which project into aligned apertures 27 formed in" the plate 15 and spacer blocks 28, the latter being secured to the corners of the plate 15 as by rivets.

29. (See Figs. 2 and 5,.) Each spacer block 28 is provided with an elongated bore 30, disposed to pass centrally through the apertures 2,7 therein, and which is adapted to receive a cotter or tie pin 31. The studs 26 are provided with longitudinal slots 32 registering with the bores 30 of the'blocks 28. the slots being of sufficient lengthto permit the desiredrelative movement of the plates 15 and 25 when thecotter pins 31 are in place. Normally, the plates 15 and 25 should be intheir extreme spaced apart osition. Arcuate springs 33 seated in suita le saddles 34, the latter secured to the plate 15, bear against the plate 25 and hold the d plate 25 in maximum spaced relation to the punch'plate 15, the pins 31 in the slots 32 limiting the distance between said plates.

The punch plate 15 carries in the apertures 16 interchangeable punch pins 35. These pins, as shown, have asquare head 36, a cylindrical body 38 and a pointed tip 39. The body portions' 38 lof the pins 35 are somewhat greater in diameter than the inner diameters of the hollow dies 13, and have a relatively close, free-moving tit in the apertures 16. The square heads 36 are of such size as to abut each other on all sides and thus present a substantially unbroken `surface to a cushion 40 of slabfrubber, which is normally interposed between the heads 36 and the backing plate 25. 4It is to be understood, however. that square-headed punch pins are not essential to my invention, sincev they serve merely to give a longer life to the cushion 40. Hexagonal and round headed pins may be employed with equallysatisl then secured to the punch plate 15 by insertion 'of the cotter pins 31 into the aligned' bores 30 in the spacer blocks 28 and slots 32 in the studs 26. The plates 10 and 15 are then opened up by swinging back the upper plate on the hinges 17, and a sheet of rubber 41, or other like material to be perforated, is placed over the lower plate in correct position to receive, in proper relation to its margin, perforations of the design set up in the punch plate 15. The sheet 41 preferably is wet to facilitate the punching operation.

The upper late is'now closed upon the lower plate, tlie interlocking of the dowel v strips and the notches 21 of the blocks 22 sizes and shapes. Further, the employmentensuring that the punch pins 35 and dies 13 are brought into accurate axial alignment. V(See Fig. 2.) The perforating device is now placed in a suitable press and the backing plate 25 and die plate 10 are .forced relatively towardeach other against the compression of the springs 33, the tie pins 31 moving -in the slots 32 of the studs 26. The punch pins 35 arethus moved into the central openings of the dies 13, the points of the'punch pins 35 first penetrating therubber sheet 41, then stretching it locally over the conical Walls of the tips and nally bringing the conically deformed portions of the sheet into lcontact with the inner edges of the dies 13. The cutting of all perforations is thus concurrently affected by-a direct pressure action, ratherv than a shearing action, which produces clean-cut perforations 42. The cushion 40 serves to equalize the cutting pressure exertedby each of the punch pins 35 and to compensate for any slight inequalities in their lengths. The severed disks v43 pass into the apertures 11 of the die plate whence they are subsequently readily removed. The device is then taken from the press, the plates opened up and the perforated sheet removed. The device iS then ready for a succeeding operation.

A particular advantage of the above de- 25 and the cushion 40 may be removed from the punch plate 15, and the design or arrangement of the punch members 35 in the apertures 16 changed either in size orconfguration to accommodate articles of various of interchangeable and separately operable punch members permits the ready replacement of defective punch members.

Alternative to the above procedure, where a wide variety of designs or sizes of sheets are to be perforated, in order to eliminate thelabor of resetting the design in the punch plate 15, I may ll all the apertures 16 in the punch plate 15 with punch pins 35 and,V

ion are not forced into the dies 13 and hence rubber or like material comprising means securing a plurality of hollow dies in spaced relation, means adapted to support a plurality of independently reciprocative punch pins adapted to be arranged in .interchangeable designs of varying sizesand shapes in alignment with said dies, and means movable relatively to said support-ing meansfor forcing said dies and punch pins into simultaneous cuttingengagement with a resilient pressure. y. y.

2. A device for perforating a sheet of rubber or like material comp-rising means securinga plurality of hollow dies in spaced relation, means for presenting a plurality of independently movable lpunch pins in alignment with certain of said dies, independently movable means for simultaneously bringing said aligned dies and punch`pins into cutting engagement, including means for distributing the pressure with substantial equality among the cooperating dies and punch pins. g l

3..A ldevice for perforatinga sheet of rubber or like material comprising means securing a plurality of hollow dies in regularly spaced relation, .means embodying a plurality of apertures disposed in the same spaced relation as the hollow dies, punchv pins adapted, to vbe inserted in said apertures in free-moving relation thereto, means for securing an alignment of the punch pinsl with the dies, and resilient means movable ,relatively to said apertured means to bring said dies and punch pins simultaneously into cutting engagement.

4. In la perforating device, in combination, a plate having a plurality of regularly spaced apertures, punch pins removably inserted in atleast some of the said apertures, a cushion adapted to engage the heads of said punch pins, a'backing plate supporting said cushion and so attached to said apertured plate as' to permit a limited movement of said plates toward and from one another, and a die-plate containing a plurality of hollow cylindrical dies in the same regular arrangement as the apertures and aligned to coact with said punch pins, lthe internal diameter of the dies being less than the diameter of the punch pins.

5. In a perforating device, in combination, an apertured plate in which a plurality of headed punch members are adapted to be inserted to form designs ofvarying sizes and shapes, means movable relatively to said apertured plate and adapted to coact -With said heads for simultaneously advancing the punch members in the said apertures, said means being removable to permit a change in design of said punch members, and a dieplate containing a plurality of hollow cylindrical dies in the same regular arrangement as the apertures and aligned to coact with said punch pins, the internal diameter of the dies being less than the diameter' of the` punch pins.

6. In a perforating device, in combination, an apertured plate in which a plurality or'. headed punch members are adapted to be inserted to form designs of varying sizes and shapes, a backing plate coact-ing with .said heads for simultaneously advancing the punch members in said apertures, and means detachably securing said backing plate to said apertured plate and permitting a limited movement of said plates toward 'and from one another.

7 In a perforating device, in combination, an apertured plate in which a plurality of headed punch members are adapted to be inserted to form designs of varying sizes and shapes, al backing plate coacting with said heads for simultaneously advancing. the

heads for simultaneously advancing the' punch members in said apertures, and means detachably securing said backing plate to said apertured plate and permitting a limited movement of said plates toward and from one another, said means including posts iixedly secured in one plate and attached to the other plate with a lost-motion connection. V

9. In a perforating device, in combination, an apertured plate in which a plurality of headed punch members are adapted to be inserted to form designs of varying sizes and shapes, a backing plate coacting with said heads for simultaneously advancing the punch members in said apertures, means detachably securing said backing plate to said apertured plate and permitting a limited movement of said plates toward one anotherq said means including posts fixedly secured in one plate and attached to the other plate with a' lost-motion connection, and springs normally holding' said plates in maximum spaced relation. y

In Witness whereof I have hereunto set my hand this 1st day of December, 1924.

JOHN R. GAMMETER. 

